Structural member



Oct. 2, 1934. L. R GRUMMAN 1,975,228

STRUCTURAL MEMBER Filed OCt,a 23, 1951 PER Z ATTOR EV Patented Oct. 2,1934 UNITED -`sfr-Ares PATENT ottici;

f signor to Montaukk l Farmingdale, N. Y.

Research Corporation,

Application october 23, 1931, serial No. 570,600

5 Claims.

This invention relates to a structural member, particularly a beam orspar and more specifically a metallic beam or spar comprised of a numberof component members which may be riveted,

i bolted or welded together to make a single member of great strengthand rigidity combined with extreme lightness.

My particular construction combines the virtues of the so-calledWandering web type of beam .i and the box girder. It has less web than abox girder for my web is applied in staggered form, but it has numerouscross web members which give great rigidity. It is simpler and easier toassemble than either the wandering web or box jgirder types and may bebuilt up of relatively inexpensive units.

The principal object of the invention is to provide a beam or sparsuitable because of its lightness and strength for use as the chiefstrength member of an airplane wing, although it may easily be adaptedfor use as a mast or boom on a sailing vessel and for other structuralpurposes where strength and lightness are of primary importance.

Other objects are to provide a member of the type described which shallpermit of ready accessibility for ease of examination and repair, andshall permit of construction in which the strength and weight may beeasily varied to meet the rejquirements of the use to which the memberis to be put. Thus if the member were required for use as the main beamof a wing extending unbroken from one wing tip to the other it would bepossible to make it of greater strength in the jcenter and of lesserstrength and weight at the extremities. Other objects are either obviousor will be hereinafter mentioned.

In the drawing in which similar reference char- I acters refer tosimilar parts in each gure,

Fig. 1 represents an end view of a built up spar constructed inaccordance with the invention,

Fig. 2 is a side view of the same spar,

Fig. 3 is a sectional View taken through Fig. 1 on the line 3-3 lookingin the direction of the i arrows,

Fig. 4 is a perspective view of the web members, and

Fig. 5 is a modification of the invention in which a reinforcing memberhas been incorporated.

Referring to the drawing, channel members 5 which may be U shaped ifdesired and which have a base 6 and parallel arms '7 form thelongitudinal members or cap pieces of a beam designated generally as 8.

Fastened to the arms 7 of the cap piece 5 in any suitable manner such asby rivets 9 or by welding are a plurality of webs 10 which may be ofsuitable metal stampings.

A web 10 is shown in detail in Fig. 4 and consists of a single piece ofmetal bent to provide a flat or web section 11, a post or cross websection 12 which is preferably slightly shorter than the inside width ofthe channel member to permit overlapping of the units, a reinforcingfoot or flange 13, and an abutment flange or head 14. The fiat sectionmay be perforated as at 15 in the interest of further lightness.Suitable holes 16 are provided to permit of riveting the web to the cappieces. The Webs are placed head to foot in interlocking engagement witheach other within the arms 7 of the cap pieces 5. Because of this headto foot staggered arrangement the interior of the spar is renderedreadily accessible and the work of placing the rivets 9 is facilitated.

The reinforcing foot 13 is placed within the abutment 14 rather thanoutside it in order that the adjoining web elements may be connectedtogether by rivets or otherwise to give added rigidity to the joist orbeam. The double web thickk ness thus formed at regular intervals alongthe length of the beam forms posts which greatly strengthen theconstruction as shown in Figure 5. This is a conspicuous advantage overthe continuous web type of construction where such reinforcement isimpractical.

The webs 10 may be of varying gauge and the heavier ones may be placedat the points of greatest strain on the beam, thereby concentratingweight and strength where it is required. Greater strength may be givento the cap piece where required by providing a larger channel member 5to t outside cap piece 5 at such points.

It will be readily seen that many modifications of this construction maybe made without departing from the scope of the invention.

I claim:

1. A structural member comprising a pair of longitudinal channelelements having their open faces in opposed relationship, a plurality ofweb elements, each having longitudinal and transverse webs, in staggeredrelationship to each other and disposed between the channels, flangemeans integral with the web elements to permit interlocking, and meansto afx the longitudinal webs to the channel elements and to the flangeof an adjacent web element to interconnect the web elements.

2. In a structural member of the type described a web element comprisinga sheet of metal having a major flat longitudinal portion, a flattransverse portion at substantially right angles to one end of thelongitudinal 'portion and a flange at the freel end ofeach portionwhereby adjacent Yweb elements may be interlockingly interconelementstherebetween and aixed thereto, said web elements having a plurality ofwebs at angles to each other, and a Yflange at the free end Vof each webwhereby the web elements may be assembled in staggered interlocking andinterconnected relationship within the longitudinal elementstoyconstitute a'continuous wandering web whereof the abutting flangesform post elements.

5. A structural member comprising a pair of longitudinal elements havinga plurality of web `elements therebetween and aflixed thereto, said webelements having a pair or" webs substantially "at -ri'g'ht angles toeach other and having a flange at the free end Vof YVeach web wherebythe Web elements :may be assembled in interlocking, overlapping,staggered relationship to form a continuous web.

LEROY R. GRUMMAN.

